Organization of construction- a system for forming or selecting a production enterprise (complex of enterprises) designed to complete the task.
Planning- a system for linking construction and installation work performed in time and space, as well as a system for the supply and consumption of material and technical resources.
Control- a system for maintaining the established order or transferring construction production from one state to another in order to unconditionally complete the task.
The basic principles of organization, planning and construction management are: centralized management of the production and economic activities of construction organizations with the maximum possible expansion of their independence; reducing the construction time of objects while simultaneously increasing and decreasing their cost; constant increase in labor productivity; comprehensive mechanization and possibly more complete automation of construction production; industrialization of production; performing construction and installation works using in-line methods; full compliance with labor protection requirements and safe performance of work; rational organization of logistics and economical use of resources; strict compliance with laws and regulations.
The construction of any building or structure of external water supply and sewerage networks and other engineering structures is associated with the production of a complex of construction processes by workers of various professions and different qualifications. Construction processes can be carried out continuously or with certain technological breaks. Thus, when laying external sewer networks with socket joints of individual pipelines, before hydraulic testing, a certain time is required for the cement mortar to harden in the socket joint. The hardening time of the solution in this complex process constitutes a technological break. Technological breaks determine more difficult conditions for organizing a continuous production process.
Construction processes in space can develop differently. During the construction of external water supply and sewerage networks, processes of a linear nature are observed; during the construction of multi-level treatment facilities, construction processes are carried out mainly in tiers.
Construction processes are carried out sequentially, in a certain technological dependence (excavation of trenches, installation of an artificial foundation, laying pipelines along a given slope, sealing joints, etc.). It is possible to organize work in such a way that a certain team of workers of a certain profession will carry out work along the entire route or throughout the entire construction site and, upon completion, will move to another site, and in its place will come the next team of workers who will perform another type of work also on the entire route or object. This method of conducting construction and installation work is called the sequential method.
With the sequential construction method, each building is erected after all work on the previous building is completed. This method of performing work by teams carrying out various construction processes is accompanied by forced breaks in work.
Construction processes can be started and completed at all sites simultaneously. In this case, the construction time of all objects will be equal to the construction time of one object, however, significant material and technical resources will be required. This method of conducting construction and installation work is called the parallel method.
In-line method construction and installation work combines sequential and parallel methods, preserving the advantages of both methods and eliminating the disadvantages of each of them separately. can be explained with the following example. Let us assume that it is necessary to lay m identical external sewer networks. The main processes for laying each of the networks will be: excavation of trenches, installation of an artificial foundation, laying of pipelines in a given direction and slope with sealing of joints, hydraulic testing and backfilling of trenches. As noted above, the execution of these processes occurs sequentially, but it is not at all necessary to wait for the end of one of the processes along the entire route to begin the next one. The entire route can be divided into sections called sections, so that at all sections the amount of work when performing basic homogeneous processes is the same. If, to carry out these volumes of work, the number of each team is taken such that the duration of its work on the grip is also the same, then the number of grips will correspond to the number of main processes as part of the complex production process. Let us denote the execution time of all processes for the construction of one Tc network, the main processes performed on the sites, with Arabic numerals 1...5 in circles (Fig. 1.1, a).
At sequential method conducting construction and installation work (Fig. 1.1, a), the time for installing m networks will be T = Tm, while the intensity of consumption of material and technical resources will be r = R/m (where R is the total resource costs for the construction of m networks). With the parallel method (Fig. 1.1.6), all networks are constructed simultaneously and the time for their installation is equal to the time for the installation of one network T = Tc, and the amount of material resources will be equal to R = gm.
In the case of performing construction and installation work using the flow method (Fig. 1.1, c), the complex process is divided into n component processes (in our case, 5), for each of which the same duration is assigned and their rhythmic execution is combined in time on different networks, ensuring thereby sequential implementation of homogeneous processes and parallel execution of heterogeneous ones. If we take one period of time corresponding to the work on the 1st network and corresponding to the 5th capture, then we can make sure that on the 1st network during this period of time the trench is backfilled, on the 2nd - a hydraulic test, on the 3rd 1st - laying pipelines in a given direction and slope with sealing of joints, 4th - installation of an artificial foundation for pipelines and 5th - cutting out a trench. However, each individual process on different networks runs sequentially.
Construction of m networks using the flow method requires less time (T< Tцm) по сравнению с последовательным, а интенсивность потребления материально-технических ресурсов меньше по сравнению с параллельным nr < mr.
To organize the construction flow, it is necessary to divide the production process into components, entrusting their implementation to workers of the relevant professions; create a production rhythm and combine the production of component processes in time.
The nature of the division of construction processes is influenced by various construction conditions: the configuration of objects, the type of work performed, etc. However, there are concepts of the flow method that are common to the entire variety of buildings and structures being erected. When distributing operations among workers, one can distinguish flow-operational, flow-partitioned and flow-complex methods of conducting work.
The flow-operational method is used when dividing the production process into operations in one link. Units of one brigade work in a flow-disaggregated manner, performing simple processes at a specific capture site. The integrated flow method is used when performing work by complex teams, in which team members have several related professions.
Depending on the configuration of construction projects and its influence on the organization of the flow method of construction, a distinction is made between flow-linear and flow-grabbing methods of work. The linear flow method is used in the construction of extended structures, which include external networks of water supply and sewerage systems. The flow-grabbing method is rational for the construction of buildings and structures for various purposes, with significant dimensions in height; are divided into single- and multi-tiered.
In construction, a complex flow is organized, consisting of specialized (private), object and complex flows. The products of the flows are: specialized - completed volumes of certain works; object - completed buildings and structures; complex - a group of buildings or structures.
Most production processes (not only construction) can be represented in the form of drawings, diagrams, graphs, tables, etc., which quite accurately reflect the reality of what is happening in these processes. These are models of the ongoing production process. Organization and planning involve the development of models for the implementation of a production process that develops in time and space. Currently, there is no established classification of modeling methods yet.
The accumulated experience in modeling the organization of construction processes in time and space (the work of professors V. A. Afanasyev, V. I. Rybalsky, V. M. Vasiliev, etc.) allows us to formulate the following basic requirements for them when developing scientifically based models: purposefulness (presence the purpose for which the model is created); adequacy (correspondence of the model to the object); completeness of the model (providing solutions to all problems of interest to the user); simplicity of the model (ensuring a good understanding of the model, protection from solving extraneous problems and issuing solutions that are far from the truth); profitability (maximum cost savings for creating and researching the model); adaptability (the ability to use the model while taking into account various factors).
In developments on the organization, planning and management of construction, the most widely used models are in the form of graphs, cyclograms, network models in the form of a graph, and a tabular form of recording models in the form.
In the example discussed above, it was supposed to build tons of identical external sewer networks. Each of the networks is divided into 5 grips, on which heterogeneous work is simultaneously performed. The sum of occupations on one network (building, structure, etc.) is called the scope of work.
With the flow method of construction and installation work, homogeneous work is carried out sequentially, dissimilar work is carried out in parallel. A flow that is formed by homogeneous jobs performed sequentially on different fronts is called a private flow. A flow formed by heterogeneous jobs performed in parallel on one front of work is called an object flow.
In Fig. 1.2 - 1.4 shows an image of the construction flow in the form of a line graph, cyclogram and.
Rice. 1.2. Line graph of construction flow
Rice. 1.3. Graph-cyclogram
Rice. 1.4. Network diagram
86. What is the essence of continuous construction? Continuous construction is a method of performing construction and installation work that ensures the systematic, rhythmic production of finished construction products based on the continuous and uniform work of labor collectives, provided with timely and complete delivery of all necessary types of material resources. Continuous construction is a kind of construction conveyor that requires timely provision of work with design documentation, continuous and complete provision of materials and products, and daily maintenance of machines, equipment and devices. Continuous construction involves dividing the process of constructing buildings and structures into separate specialized sets of work (construction flows), carried out continuously with the transition of workers at a calculated speed from one particular front of work to another.
87. By what methods can non-flow construction be organized? Non-flow construction can be organized by two methods: sequential and parallel. With the sequential method, each new structure is built after the previous one is built. With the parallel method, the duration of construction of one building is equal to the duration of construction of all identical objects. With the sequential method, the duration of construction of a complex of buildings with intermittent execution of the same type of work and the same consumption of material resources is maximum. With the parallel method, the minimum possible duration of construction of a complex of objects is ensured and at the same time the maximum consumption of material and labor resources.
88. What are the advantages of continuous construction? With continuous construction, the completion of construction of complexes of objects will occur faster than with the sequential method; At the same time, the consumed material and labor resources will decrease compared to the parallel construction method. The flow method ensures uniform loading of crews, uniform consumption of resources and rhythmic release of finished construction products. This method creates favorable conditions for the work of related companies - subcontractors, supply and transport organizations, and construction industry factories. During continuous construction, the minimum necessary and constantly renewable construction reserves are formed, which, by reducing the overall duration of construction and the systematic commissioning of facilities, leads to a reduction in the volume of unfinished construction and an increase in the efficiency of capital investments. Practice has shown that improving continuous construction methods is a great reserve for reducing construction time and reducing its cost.
Example. A construction organization is tasked with the construction of five identical houses. We conventionally assume that the labor intensity of work on the underground and above-ground parts of the building and the labor intensity of finishing work are equivalent. Let's consider three options for the work schedule using different methods (Fig. 1 a, b, c). With a sequential method of conducting work, the construction of all houses will take fifteen months with an uneven workload of construction teams and the same material support.
With the parallel method of conducting work, the construction of five houses will take three months, with the need to triple the staff of the construction department and the huge simultaneous consumption of material resources. With the continuous construction method of these houses, their construction will take seven months with an even expenditure of material and labor resources.
89. What needs to be done to organize the construction of a complex of facilities using the in-line method? To organize the construction of facilities using the in-line method, it is necessary to: – divide the complex production process into component processes; – divide labor between performers and assign these processes to them; – create a production rhythm of construction: divide the entire front of construction work into sections and set the duration of each process on them; – carry out technological linking of the execution of individual processes with each other: assign a sequence of work on the work areas in such a way that the execution of dissimilar processes is maximally combined in time and space.
90. What is the front of construction work called? Under the front of construction work, a technological space is assumed, within which construction and installation work is carried out in accordance with the assignment received. A work front is a part of an object or structure allocated to the production team to ensure uninterrupted work for a certain period of time (but not less than a shift). The dimensions of the work area should be taken from the calculation of the correct and safe placement of workers and the tools and mechanisms at their disposal in this area. An occupation, a section of a building, a section of a floor, or a tier can be taken as the front of work.
91. What is called capture? A section of the work front allocated to a team to work for a certain time to obtain finished products is called a capture. The dimensions of the work front, areas and plots are usually determined by area (m2) or length (m).
92. What is called a plot? The capture area allocated for work by a brigade unit is called a plot.
93. What is called a tier? As a building or structure is erected in height, the level of the workplace changes. The height zone within which a part of a building or structure is being erected from one workplace is called a tier.
94. How are grip sizes determined? The sizes of the grips are assigned in such a way that the duration of execution of individual processes on the grip is a unit of time, not less than one shift. The location of the boundaries of the occupation must coincide with the architectural, planning and structural element of the structure. This could be an apartment or a section in a residential building, a span of a building or part of it, foundations for technological equipment, etc. The duration of work on a tier can be taken as a multiple of half the work shift.
95. What types of flows are possible? Classification of flows is carried out depending on the structure and type of final construction product. There are private, specialized, object and complex flows.
96. What is a private thread? A private flow is an elementary construction flow, which represents one or more processes performed by one team (team or unit). The products of the private flow are structural elements of buildings or structures (excavation work, installation of foundations, masonry of walls, plastering work, installation of water supply, heating, etc.). A private flow is organized where it is possible to carry out construction and installation work on different sections using the flow-dissected method.
97. What is a dedicated thread? A specialized flow is a set of technologically related private flows, the joint product of which is either a structural element of a building or a separate type of work. As an example of a specialized flow, one could cite roofing work: in this case, the device of vapor barrier, insulation, screed, roofing carpet are individually private flows, and together a structural element: the roof.
98. In what directions can private and specialized flows develop? Private and specialized flows can have different directions of development: horizontal, vertical, inclined, mixed. The horizontal direction of flow is carried out, for example, when constructing foundations, installing structures of one floor, roofing work, etc. The vertical direction of flow development can be vertically ascending, vertically descending, or in combinations thereof. For example: brickwork of pipes (vertical upward flow); painting work in residential buildings (vertical-downward flow). With an inclined flow development pattern, structures are installed on different floors, floor brickwork, etc. A mixed flow direction is formed with combined patterns. The predominant pattern of flow development in multi-story construction is horizontal-vertical, in single-story construction it is horizontal.
99. What is an object stream? An object flow is a set of technologically and organizationally related specialized flows, the joint products of which are completed individual buildings, structures or a group of buildings, or the construction of a residential area, utilities, etc.
100. What is complex flow? A complex flow is a group of organizationally related object flows, united by a common product in the form of a complex of industrial enterprise structures, buildings, structures. The products of the complex flow are commissioned industrial facilities, residential areas, etc.
101. What types of rhythmic flows can there be? According to the nature of rhythmicity, flows can be rhythmic, heterorhythmic and non-rhythmic. A rhythmic flow is a flow in which all its constituent flows have a single rhythm: the duration of work performed by each individual team in their work areas is the same. A heterorhythmic flow is a flow in which its constituent flows have the same rhythms and different rhythms of different types of flows. An irregular flow is a flow in which the duration of work performed by each team on the grips is not the same. Irrhythmic construction flows are designed for the construction of objects of complex configuration in plan, with different heights of rooms and uneven distribution of work volumes in space. It is difficult to divide such objects into grips of equal labor intensity. Therefore, the duration of work on occupations by individual teams, which have a constant number of personnel during the construction process, is different.
102. What types of flows are distinguished by duration?? Based on the duration of construction, a distinction is made between short-term and continuous flows. Short-term flow is carried out during the construction of individual buildings or structures, or a group of such objects. The continuous flow operates for a long time and covers the work program carried out by the construction and installation organization over several years. Continuous flows create conditions for the rhythmic work of construction organizations and allow better use of labor and material resources and a fleet of construction machines. Such a continuous flow favors the stable operation of transport organizations and construction industry enterprises.
103. What is the peculiarity of flow methods in industrial construction? In industrial construction, as a rule, heterorhythmic flows are used with various combinations of variable parameters. This is due to the construction of heterogeneous buildings and structures with different character of their space-planning solutions. The flow organization of construction in these conditions becomes much more difficult than in housing construction. In order to prevent excessive differences in the labor intensity of work on sections of one flow (this entails a decrease in output and reduces the efficiency of machine use, which affects the pace of construction), parallel flows are organized in groups of similar units and objects.
When constructing railways, the following work methods can be used
- consistent
- parallel
- in-line
- combined
At sequential method Construction organizations create complex teams, whose workers first perform work at the first site, and after their complete completion move on to the next and then to the rest.
The duration of construction of objects T will be maximum, the sum of the construction time of all objects t, while the need for human resources will be minimal. Each type of resource will be used periodically during the construction process; Each stage of construction requires workers of different specialties, different machines and materials. This can be partially mitigated by using workers with several specialties, using universal machines suitable, for example, for carrying out work on the construction of foundations and the installation of building walls. With this method of organization, it is necessary to construct and strictly adhere to schedules for the delivery of machines and materials, and the movement of labor.
At parallel method a minimum construction duration T is ensured, equal to the construction period of one object t.
The need for resources will be maximum. However, even in this case, the types and quantities of resources consumed change over construction periods. When using this method, as well as the sequential one, complex teams are created (in this case to work at each of the facilities), responsible for timely and high-quality work, and delivery of the facility to the customer in full.
At flow method The construction process at sites is divided into types of work or work processes, in which specialized teams or units participate. At the same time, labor productivity increases, since performers perform the same work for a long time. Their work skills are improved, specialized equipment and devices are better used, costs of moving from one site to another are reduced, and the use of machines is improved, since there are no technological and organizational intervals in the work of teams. Homogeneous material and human resources are used evenly over a long period.
Combined method used in organizing the construction of complex objects (this includes the railway). When it is used on a number of objects included in the construction complex, work is carried out using a sequential method, on others - parallel, on others - in-line. In general, construction is carried out using a combined method. A variation of the combined method is the integrated flow method of organization. When used in organizing the construction of railways, units, moving along the railway route, perform rhythmically construction and installation work in the established technological sequence, in compliance with the specified pace and deadlines. At the same time, at certain intervals, sections of the road are constructed that are suitable for opening the sequential working movement of trains for temporary and permanent operation. However, when using this method, units must be equipped with the necessary mechanization equipment and labor to allow work to be carried out in accordance with a given pace.
It should also be noted that when conducting construction using sequential and parallel methods, elements of threading are encountered when performing certain types of work.
The parallel-flow method of organizing work is used to reduce construction time and consists in the fact that certain types of work are performed by several teams of the same type.
This method requires careful justification because:
is an extensive way to reduce construction time;
in some cases, the involvement of additional teams, especially low-power ones, can lead not to a reduction, but to an increase in the total duration of work.
The parallel-flow method of organizing work is formed on the basis and after calculating the non-rhythmic flow of MCR, while two problems are solved:
1. determine for what types of work or work and how many additional teams to attract;
2. how to distribute work between teams of the same type (i.e., give a work schedule for these teams, the loading time for these teams).
A. V. Afanasyev proposed two ways to solve the problem:
assign additional teams of the same type to the longest types of work in numbers that ensure their duration is reduced to the required amount;
distribute work between teams of the same type during flow calculations with critical work identified taking into account resource and frontal connections; distribute work in accordance with the initial priority with priority loading (with equal capabilities) of the most powerful teams, and with equal power of teams - those of them that have the lowest serial number.
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Brigade capacity:; B 2 = B 1 ; B 3 = 2 B 2 ; IN 2 = B 1 . |
The calculation showed that, in comparison with the schedule for the MKR, the involvement of additional teams made it possible to reduce the construction period of the facility by 7 days. It turned out that the need to attract brigade B 3 disappeared.
In general, the PMMOR requires consideration of several options, both in determining the number of additional teams, tick and in scheduling their loading.
Lecture 8
Options for organizing work can be assessed according to certain indicators (criteria).
When assessing options for organizing work, various individual criteria can be used (taking into account their priorities) and differential ones, combined (taking into account their significance) into an integral one.
Individual criteria are presented, as a rule, in absolute terms (in terms of cost, time, labor costs and other natural indicators):
Duration of work.
Worker movement schedule indicators.
Number of types of work.
Unevenness coefficient
Labor intensity of work.
Differential criteria are always presented in relative values, limited by a certain limit (from 0 - very bad to 1 - very good). They are combined, taking into account the significance coefficients, into an integral one. In this case, significance coefficients are set (accepted) by developers or a higher level of management, taking into account specific production conditions and a more general one in relation to the problem under consideration.
The experience of industrial production shows that the best method of organizing it is a production flow system characterized by uniformity and continuity of the technological process.
Continuity and uniformity of production are expressed in continuous and uniform consumption of labor and material and technical resources, as well as in continuous and uniform production. This leads to an improvement in all indicators: production is accelerated; with the same production capacity, production output increases; its quality improves; labor intensity and cost of production are reduced.
The principle of continuity and uniformity is also the basis of continuous construction.
The essence of the construction flow can be represented by the following diagram (Fig. 1).
As can be seen from the diagram, if it is necessary to build m identical buildings (to produce m units of construction products), then their construction can be organized using different methods: sequential, parallel, in-line.
The sequential method provides for a work order in which each subsequent building is erected after the completion of the previous one.
The parallel method involves the simultaneous construction of all buildings.
The flow method is a combination of sequential and parallel, in which the disadvantages are eliminated to the greatest extent and the advantages of each of them are preserved. With the flow method, the technological process of constructing a building is divided into n component processes (laying foundations, erecting walls and ceilings, installing a roof, finishing work), assigning the same duration to each of them and combining their rhythmic execution over time on different buildings, ensuring the sequential execution of homogeneous processes and parallel - heterogeneous.
Rice. 1. Comparative characteristics:
a - sequential; b - parallel; c - in-line methods
With the sequential method, the duration m of construction of buildings
and intensity of resource consumption per unit of time
where Tc is the duration of the production cycle for the construction of one building;
R is the total cost of resources for the construction of t buildings.
With the parallel method, production is accelerated: the total duration of construction of m buildings is the duration of one production cycle - Tc, but the intensity of resource consumption increases m times.
Continuous construction of m buildings requires less time than sequential construction (T
Therefore, the flow production method is an effective combination of serial and parallel.
To create a construction flow you need:
1) divide the construction production process into component processes and operations;
2) divide labor between performers;
3) create a production rhythm;
4) combine the execution of the component processes as much as possible in time.
Continuous construction can have different rates: from the slowest to the most accelerated. This depends on the assigned rhythm of production, the number of workers employed, and the number and power of construction machines used. The choice of one or another pace is made taking into account the given pace of construction and the possibility of providing it with labor, material and technical resources.
In some cases, there is a need to construct a building or structure as soon as possible. Then a high-speed method is used, based on carrying out work in the shortest, technically possible and economically feasible time by using the greatest combination of work in time and using the maximum possible day for arranging the number of workers and construction equipment (machines, devices).
High-speed methods, which are appropriate in some cases for the construction of large buildings or structures, often turn out to be ineffective and practically unacceptable due to the significant and short-term intensity of resource consumption, since high-speed construction is mainly based on the principle of parallel production.
The flow-high-speed method, which has the advantages of the tray and high-speed methods, is most widely used in construction. The flow-high-speed construction method is a method of organizing production that ensures the shortest possible work time and is characterized by continuous and uniform consumption of labor, material and technical resources, as well as continuous and uniform production of products with a minimum intensity of resource consumption.
The flow-speed method can be used:
a) in individual construction processes;
b) in the construction of individual buildings;
c) during the construction of a complex of structures (development of a block, village).
In all these cases there is a limited short-term construction flow; a flow object is a process, building or group of plants that is completed within a more or less short period of time, after which production must be rebuilt in connection with the transition to the construction of new facilities.
In contrast to such short-term limited use of the flow-speed method, one should consider its variety - the so-called long-term, or continuous flow. This method is based on long-term flow-speed work of a construction organization of a certain production capacity, capable of efficiently, evenly and continuously using means of production for a long time without reducing productivity and restructuring.
In contrast to short-term, limited flows, where the objects for applying flow are individual construction processes, buildings or complexes of buildings, the objects for creating a continuous construction flow are specialized construction organizations of appropriate production capacity, provided with all types of production resources and design documentation.
